研究者業績

市原 佐保子

イチハラ サホコ  (Sahoko Ichihara)

基本情報

所属
自治医科大学 医学部 環境予防医学講座 教授
学位
医学博士(名古屋大学)

J-GLOBAL ID
200901089139977563
researchmap会員ID
5000079149

外部リンク

論文

 159
  • Yuji Fujitani, Akihiko Ikegami, Kouta Morikawa, Jun Kumoi, Takeo Yano, Atsushi Watanabe, Ai Shiono, Chuichi Watanabe, Norio Teramae, Gaku Ichihara, Sahoko Ichihara
    Journal of hazardous materials 467 133679-133679 2024年4月5日  
    Focusing on the relatively unexplored presence of micro- and nano-plastic aerosol particles, this study quantitatively assessed the emission of nano-plastic particles during the machining of carbon fiber reinforced plastic (CFRP) in the working environment. Measurements of aerosol particles smaller than 1 µm in size were performed by aerosol mass spectrometry. The findings revealed that concentrations of carbonous aerosol particles (organic aerosol and refractory black carbon (rBC)) were higher during working hours than during non-working hours. Positive matrix factorization identified CFRP particles as a significant source, contributing an average of approximately 30% of concentration of carbonous aerosol particles during working hours. This source apportionment was corroborated by the presence of bisphenol A and F fragments, principal components of the epoxy resins used in CFRP, and was corroborated by similarities to the carbon cluster ion distribution observed in rBC during CFRP pipe-cutting operations. Further, the particle size distribution suggested the existence of plastic aerosol particles smaller than 100 nm. This study established the method to quantitatively distinguish nano-plastic aerosol particles from other aerosol particles in high temporal resolution and these techniques are useful for accurately assessing exposure to nano-plastic aerosol particles in working environments.
  • Ryoya Takizawa, Akihiko Ikegami, Cai Zong, Syun Nemoto, Yuki Kitamura, Nathan Mise, Gaku Ichihara, Sahoko Ichihara
    Fundamental Toxicological Sciences 11(3) 109-121 2024年  
  • Alzahraa Fergany, Cai Zong, Frederick Adams Ekuban, Bin Wu, Satoshi Ueha, Shigeyuki Shichino, Kouji Matsushima, Yoichiro Iwakura, Sahoko Ichihara, Gaku Ichihara
    Archives of toxicology 2023年11月16日  
    Acrylamide is an environmental electrophile that has been produced in large amounts for many years. There is concern about the adverse health effects of acrylamide exposure due to its widespread industrial use and also presence in commonly consumed foods and others. IL-1β is a key cytokine that protects the brain from inflammatory insults, but its role in acrylamide-induced neurotoxicity remains unknown. We reported recently that deletion of IL-1β gene exacerbates ACR-induced neurotoxicity in mice. The aim of this study was to identify genes or signaling pathway(s) involved in enhancement of ACR-induced neurotoxicity by IL-1β gene deletion or ACR-induced neurotoxicity to generate a hypothesis mechanism explaining ACR-induced neurotoxicity. C57BL/6 J wild-type and IL-1β KO mice were exposed to ACR at 0, 12.5, 25 mg/kg by oral gavage for 7 days/week for 4 weeks, followed by extraction of mRNA from mice cerebral cortex for RNA sequence analysis. IL-1β deletion altered the expression of genes involved in extracellular region, including upregulation of PFN1 gene related to amyotrophic lateral sclerosis and increased the expression of the opposite strand of IL-1β. Acrylamide exposure enhanced mitochondria oxidative phosphorylation, synapse and ribosome pathways, and activated various pathways of different neurodegenerative diseases, such as Alzheimer disease, Parkinson disease, Huntington disease, and prion disease. Protein network analysis suggested the involvement of different proteins in related to learning and cognitive function, such as Egr1, Egr2, Fos, Nr4a1, and Btg2. Our results identified possible pathways involved in IL-1β deletion-potentiated and ACR-induced neurotoxicity in mice.
  • Walaa Slouma Hamouda Abd El Naby, Cai Zong, Alzahraa Fergany, Frederick Adams Ekuban, Saleh Ahmed, Yousra Reda, Harue Sato, Sahoko Ichihara, Natsuko Kubota, Shinya Yanagita, Gaku Ichihara
    International journal of molecular sciences 24(12) 2023年6月8日  
    Epidemiological studies showed the association between air pollution and dementia. A soluble fraction of particulate matters including polycyclic aromatic hydrocarbons (PAHs) is suspected to be involved with the adverse effects of air pollution on the central nervous system of humans. It is also reported that exposure to benzopyrene (B[a]P), which is one of the PAHs, caused deterioration of neurobehavioral performance in workers. The present study investigated the effect of B[a]P on noradrenergic and serotonergic axons in mouse brains. In total, 48 wild-type male mice (10 weeks of age) were allocated into 4 groups and exposed to B[a]P at 0, 2.88, 8.67 or 26.00 µg/mice, which is approximately equivalent to 0.12, 0.37 and 1.12 mg/kg bw, respectively, by pharyngeal aspiration once/week for 4 weeks. The density of noradrenergic and serotonergic axons was evaluated by immunohistochemistry in the hippocampal CA1 and CA3 areas. Exposure to B[a]P at 2.88 µg/mice or more decreased the density of noradrenergic or serotonergic axons in the CA1 area and the density of noradrenergic axons in the CA3 area in the hippocampus of mice. Furthermore, exposure to B[a]P dose-dependently upregulated Tnfα at 8.67 µg/mice or more, as well as upregulating Il-1β at 26 µg/mice, Il-18 at 2.88 and 26 µg/mice and Nlrp3 at 2.88 µg/mice. The results demonstrate that exposure to B[a]P induces degeneration of noradrenergic or serotonergic axons and suggest the involvement of proinflammatory or inflammation-related genes with B[a]P-induced neurodegeneration.
  • Bo Wang, Boxuan Liang, Yuji Huang, Zhiming Li, Bingli Zhang, Jiaxin Du, Rongyi Ye, Hongyi Xian, Yanhong Deng, Jiancheng Xiu, Xingfen Yang, Sahoko Ichihara, Gaku Ichihara, Yizhou Zhong, Zhenlie Huang
    ADVANCED SCIENCE 2023年5月  
    Exposure to micro- and nanoplastics (MNPs) is common because of their omnipresence in environment. Recent studies have revealed that MNPs may cause atherosclerosis, but the underlying mechanism remains unclear. To address this bottleneck, ApoE(-/-) mice are exposed to 2.5-250 mg kg(-1) polystyrene nanoplastics (PS-NPs, 50 nm) by oral gavage with a high-fat diet for 19 weeks. It is found that PS-NPs in blood and aorta of mouse exacerbate the artery stiffness and promote atherosclerotic plaque formation. PS-NPs activate phagocytosis of M1-macrophage in the aorta, manifesting as upregulation of macrophage receptor with collagenous structure (MARCO). Moreover, PS-NPs disrupt lipid metabolism and increase long-chain acyl carnitines (LCACs). LCAC accumulation is attributed to the PS-NP-inhibited hepatic carnitine palmitoyltransferase 2. PS-NPs, as well as LCACs alone, aggravate lipid accumulation via upregulating MARCO in the oxidized low-density lipoprotein-activated foam cells. Finally, synergistic effects of PS-NPs and LCACs on increasing total cholesterol in foam cells are found. Overall, this study indicates that LCACs aggravate PS-NP-induced atherosclerosis by upregulating MARCO. This study offers new insight into the mechanisms underlying MNP-induced cardiovascular toxicity, and highlights the combined effects of MNPs with endogenous metabolites on the cardiovascular system, which warrant further study.
  • Yuki Kitamura, Shinji Oikawa, Jie Chang, Yurie Mori, Gaku Ichihara, Sahoko Ichihara
    Antioxidants 12(4) 844-844 2023年3月31日  
    Based on the known role of oxidative stress in the pathogenesis and progression of metabolic syndrome, we used two-dimensional gel electrophoresis with immunochemical detection of protein carbonyls (2D-Oxyblot) to characterize the carbonylated proteins induced by oxidative stress in spontaneously hypertensive rats/NDmcr-cp (CP), an animal model of metabolic syndrome. We also profiled the proteins that showed change of expression levels in their epididymal adipose tissue at the pre-symptomatic (6-week-old) and the symptomatic (25-week-old) stages of the metabolic syndrome. Two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS) was used to analyze proteins extracted from the epididymal adipose tissue. The up-regulated proteins identified at the pre-symptomatic stage were mainly associated with ATP production and redox reaction, while the down-regulated proteins found at the symptomatic stage were involved in antioxidant activity and the tricarboxylic acid (TCA) cycle. Further analysis using the 2D-Oxyblot showed significantly high carbonylation levels of gelsolin and glycerol-3-phosphate dehydrogenase [NAD+] at the symptomatic stage. These results suggest that reduced antioxidant capacity underlies the increased oxidative stress state in the metabolic syndrome. The identified carbonylated proteins, including gelsolin, are potential targets that may act as key regulators in the progression of the metabolic syndrome.
  • Md. Shiblur Rahaman, Nathan Mise, Akihiko Ikegami, Cai Zong, Gaku Ichihara, Sahoko Ichihara
    Chemosphere 318 137911-137911 2023年3月  
  • Mizuho Suzuki, Kyosuke Takeshita, Yuki Kitamura, Marie Kuribayashi, Zhenlie Huang, Gaku Ichihara, Shinji Oikawa, Sahoko Ichihara
    BIOMEDICINES 11(2) 2023年2月  
    Diabetes mellitus (DM) is a pro-thrombotic state that can potentially cause serious cardiovascular complications. Platelet hyperactivation plays an important role in these pathological processes, however there is little or no information on the effect of hyperglycemia on platelet proteins. The aim of this study was to identify the molecular targets associated with platelet reactivity under hyperglycemia. Towards this goal, we examined the effects of the exposure of platelets to 1 and 2 h glucose (300 mg/dL) and control (vehicle and osmolality control using mannitol) on platelet proteins (n = 4 samples per group) using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with MALDI-TOF/TOF tandem mass spectrometry. Two-hour exposure to glucose significantly up-regulated the expression of ATP synthase subunit beta, filamin-A, and L-lactate dehydrogenase A chain in platelets. Pro-Q Diamond staining confirmed the effect of 2 h glucose on vinculin, heat shock protein HSP 90-alpha, filamin-A, and fructose-bisphosphate aldolase A (platelet phosphorylated proteins). The identified proteins are involved in various cellular processes and functions and possibly in platelet reactivity under hyperglycemic conditions.
  • 山崎 京香, Sandra VRANIC, 渡邊 英里, 宮川 佳洋子, 竹内 咲恵, 長田 百合果, 市原 佐保子, Wenting WU, 宗 才, 櫻井 敏博, 佐藤 聡, 原 泰志, 寺島 裕也, 松島 綱治, 鈴木 利宙, 安部 良, Sonja BOLAND, Lang TRAN, 市原 学
    日本毒性学会学術年会 50.1 P1-067S 2023年  
    【目的】近年、ナノマテリアルは様々な分野で利用が拡大しているのに対し、その安全性は未だ研究途上である。非晶質シリカナノ粒子(OH-SiO2NPs)は、広範に使用されているナノマテリアルだが、アミノ基やカルボキシル基などで修飾を受けたSiO2NPsと比較して、in vivoで肺胞マクロファージを減少させるとともに、in vitroでマウスマクロファージ細胞株RAW264.7の細胞生存率を著しく低下させることが先行研究により明らかになっている。本研究は、in vitroでOH-SiO2NPsによるマクロファージ傷害メカニズムを検討した。 【方法】マウスマクロファージ細胞株RAW264.7をOH-SiO2NPsに曝露し、各種プログラム細胞死経路の阻害剤を処置することで、細胞傷害と各細胞死経路との関係を検討した。また、炎症性ケモカイン、サイトカインのmRNA発現量をRT-qPCRにより測定した。 【結果・考察】OH-SiO2NPsによって引き起こされた細胞生存率の低下は、各種阻害剤を単独で処置しても有意な改善は見られなかったが、非特異的カスパーゼ阻害剤とネクロトーシス阻害剤を同時に処置すると一定の改善傾向が見られた。このことから、OH-SiO2NPsによる細胞死にはアポトーシスまたはネクロトーシス経路の部分的関与が示唆された。また、RT-qPCRで測定したMIP-2, IL-1β, MCP-1, TNF-αのmRNA発現は、コントロール群と比較してOH-SiO2NPs曝露群で有意に上昇していた。この結果から、OH-SiO2NPsへの曝露がマクロファージの炎症性ケモカイン、サイトカインの発現を誘導することがわかったが、ケモカイン、サイトカインの細胞死における役割についてはさらなる研究が必要である。
  • Radwa Sehsah, Wenting Wu, Sahoko Ichihara, Naozumi Hashimoto, Cai Zong, Kyoka Yamazaki, Harue Sato, Ken Itoh, Masayuki Yamamoto, Ahmed Ali Elsayed, Soheir El-Bestar, Emily Kamel, Gaku Ichihara
    Toxicology Letters 370 24-34 2022年11月  
  • Abigail Ekuban, Shigeyuki Shichino, Cai Zong, Frederick Adams Ekuban, Kazuo Kinoshita, Sahoko Ichihara, Kouji Matsushima, Gaku Ichihara
    Scientific reports 12(1) 11222-11222 2022年7月2日  
    1,2-Dichloropropane (1,2-DCP), a synthetic organic solvent, has been implicated in causality of cholangiocarcinoma (bile duct cancer). 1,2-DCP-induced occupational cholangiocarcinoma show a different carcinogenic process compared to common cholangiocarcinoma, but its mechanism remains elusive. We reported previously that exposure of MMNK-1 cholangiocytes co-cultured with THP-1 macrophages, but not monocultured MMNK-1 cholangiocytes, to 1,2-DCP induced activation-induced cytidine deaminase (AID) expression, DNA damage and ROS production. The aim of this study was to identify relevant biological processes or target genes expressed in response to 1,2-DCP, using an in vitro system where cholangiocytes are co-cultured with macrophages. The co-cultured cells were exposed to 1,2-DCP at 0, 0.1 or 0.4 mM for 24 h, and then the cell lysates were assessed by transcriptome analysis. 1,2-DCP upregulated the expression of base excision repair genes in MMNK-1 cholangiocytes in the co-cultures, whereas it upregulated the expression of cell cycle-related genes in THP-1 macrophages. Activation of the base excision repair pathway might result from the previously observed DNA damage in MMNK-1 cholangiocytes co-cultured with THP-1 macrophages, although involvement of other mechanisms such as DNA replication, cell death or other types of DNA repair was not disproved. Cross talk interactions between cholangiocytes and macrophages leading to DNA damage in the cholangiocytes should be explored.
  • Jun Kumoi, Akihiko Ikegami, Yuji Fujitani, Kota Morikawa, Gaku Ichihara, Takeo Yano, Sahoko Ichihara
    International archives of occupational and environmental health 2022年2月25日  
    OBJECTIVES: Carbon fibers are used in a variety of industrial applications, based on their lightweight and high stiffness properties. There is little information on the characteristics and exposure levels of debris generated during the factory processing of carbon fibers or their composites. This study revisits the general assumption that carbon fibers or their debris released during composite processing are considered safe for human health. METHODS: The present interventional study was conducted at a factory located in Japan, and involved on-site collection of debris generated during the industrial processing of polyacrylonitrile (PAN)-based carbon-fiber-reinforced plastic (CFRP). The debris were collected before being exhausted locally from around different factory machines and examined morphologically and quantitatively by scanning electron microscopy. The levels of exposure to respirable carbon fibers at different areas of the factory were also quantified. RESULTS: The collected debris mainly contained the original carbon fibers broken transversely at the fiber's major axis. However, carbon fiber fragments morphologically compatible with the WHO definition of respirable fibers (length: > 5 μm, width: < 3 μm, length/width ratio: > 3:1) were also found. The concentrations of respirable fibers at the six examined factory areas under standard working conditions in the same factory were below the standard limit of 10 fibers/L, specified for asbestos dust-generating facilities under the Air Pollution Control Law in Japan. CONCLUSIONS: Our study identified potentially dangerous respirable fibers with high aspect ratio, which was generated during the processing of PAN-based CFRP. Regular risk assessment of carbon fiber debris is necessary to ensure work environment safety.
  • Ryoya Takizawa, Sahoko Ichihara, Cai Zong, Kazuo Kinoshita, Toshihiro Sakurai, Akihiko Ikegami, Nathan Mise, Gaku Ichihara
    Toxicology letters 349 134-144 2021年10月1日  
    Recent epidemiological studies reported cases of cholangiocarcinoma in workers exposed to 1,2-dichloropropane (1,2-DCP) in an offset proof printing factory in Japan. The present study investigated the effects of 1,2-DCP on the expression of histone family member X (H2AX) phosphorylated on Ser 139 (γ-H2AX), a marker of DNA double strand break, in human immortalized cholangiocytes MMNK-1 cells. Mono-cultures of MMNK-1 cells and co-cultures of MMNK-1 cells with THP-1 macrophages were exposed to 1,2-DCP at concentrations of 100 and 500 μM for 24 h. Expression of γ-H2AX was visualized by immunofluorescence staining. Exposure to 1,2-DCP had no effect on the expression of γ-H2AX in mono-cultured MMNK-1 cells, but significantly increased the number of nuclear foci stained by γ-H2AX in MMNK-1 cells co-cultured with THP-1 macrophages. Exposure to 1,2-DCP also significantly increased the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in co-cultured MMNK-1 cells. The results suggest that macrophages play a critical role by producing cytokines in 1,2-DCP-induced DNA double strand break in MMNK-1 cells.
  • Md Shiblur Rahaman, Md Mostafizur Rahman, Nathan Mise, Md Tajuddin Sikder, Gaku Ichihara, Md Khabir Uddin, Masaaki Kurasaki, Sahoko Ichihara
    Environmental pollution (Barking, Essex : 1987) 289 117940-117940 2021年8月10日  
    Arsenic is a well-recognized environmental contaminant that occurs naturally through geogenic processes in the aquifer. More than 200 million people around the world are potentially exposed to the elevated level of arsenic mostly from Asia and Latin America. Many adverse health effects including skin diseases (i.e., arsenicosis, hyperkeratosis, pigmentation changes), carcinogenesis, and neurological diseases have been reported due to arsenic exposure. In addition, arsenic has recently been shown to contribute to the onset of non-communicable diseases, such as diabetes mellitus and cardiovascular diseases. The mechanisms involved in arsenic-induced diabetes are pancreatic β-cell dysfunction and death, impaired insulin secretion, insulin resistance and reduced cellular glucose transport. Whereas, the most proposed mechanisms of arsenic-induced hypertension are oxidative stress, disruption of nitric oxide signaling, altered vascular response to neurotransmitters and impaired vascular muscle calcium (Ca2+) signaling, damage of renal, and interference with the renin-angiotensin system (RAS). However, the contributions of arsenic exposure to non-communicable diseases are complex and multifaceted, and little information is available about the molecular mechanisms involved in arsenic-induced non-communicable diseases and also no suitable therapeutic target identified yet. Therefore, in the future, more basic research is necessary to identify the appropriate therapeutic target for the treatment and management of arsenic-induced non-communicable diseases. Several reports demonstrated that a daily balanced diet with proper nutrient supplements (vitamins, micronutrients, natural antioxidants) has shown effective to reduce the damages caused by arsenic exposure. Arsenic detoxication through natural compounds or nutraceuticals is considered a cost-effective treatment/management and researchers should focus on these alternative options. This review paper explores the scenarios of arsenic contamination in groundwater with an emphasis on public health concerns. It also demonstrated arsenic sources, biogeochemistry, toxicity mechanisms with therapeutic targets, arsenic exposure-related human diseases, and onsets of cardiovascular diseases as well as feasible management options for arsenic toxicity.
  • Abigail Ekuban, Cai Zong, Frederick Adams Ekuban, Yusuke Kimura, Ryoya Takizawa, Kota Morikawa, Kazuo Kinoshita, Sahoko Ichihara, Seiichiroh Ohsako, Gaku Ichihara
    Toxics 9(6) 2021年6月1日  
    1,2-Dichloropropane (1,2-DCP), a synthetic chlorinated organic compound, was extensively used in the past in offset color proof-printing. In 2014, the International Agency for Research on Cancer (IARC) reclassified 1,2-DCP from its initial Group 3 to Group 1. Prior to the reclassification, cholangiocarcinoma was diagnosed in a group of workers exposed to 1,2 -DCP in an offset color proof-printing company in Japan. In comparison with other forms of cholangiocarcinoma, 1,2-DCP-induced cholangiocarcinoma was of early onset and accompanied by extensive pre-cancerous lesions in large bile ducts. However, the mechanism of 1,2-DCP-induced cholangiocarcinoma is poorly understood. Inflammatory cell proliferation was observed in various sites of the bile duct in the noncancerous hepatic tissues of the 1,2-DCP-induced cholangiocarcinoma. The aim of this study was to enhance our understanding of the mechanism of 1,2-DCP-related cholangiocarcinogenesis. We applied an in vitro system to investigate the effects of 1,2-DCP, using MMNK-1 cholangiocytes cultured alone or with THP-1 macrophages. The cultured cells were exposed to 1,2-DCP at 0, 0.1, 0.2, 0.4, and 0.8 mM for 24 h, and then assessed for cell proliferation, cell cytotoxicity, DNA damage, and ROS production. Exposure to 1,2-DCP increased proliferation of MMNK-1 cholangiocytes cultured alone, but not those cultured with macrophages. 1,2-DCP also increased LDH cytotoxicity, DNA damage, and ROS production in MMNK-1 cholangiocytes co-cultured with macrophages but not those cultured alone. 1,2-DCP increased TNFα and IL-1β protein expression in macrophages. The results highlight the role of macrophages in enhancing the effects of 1,2-DCP on cytotoxicity, ROS production, and DNA damage in cholangiocytes.
  • Frederick Adams Ekuban, Cai Zong, Madoka Takikawa, Kota Morikawa, Toshihiro Sakurai, Sahoko Ichihara, Ken Itoh, Masayuki Yamamoto, Seiichiroh Ohsako, Gaku Ichihara
    Toxicology 456 152785-152785 2021年5月30日  
    Acrylamide (ACR), a recognized neurotoxicant in humans and experimental animals, is widely used in industry and in food generated through Maillard reaction. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of the cellular defense system and activates antioxidants and cytoprotective genes. The exact roles of Nrf2 in environmental electrophile-induced neurotoxicity is poorly understood. The aim of this study was to determine the roles of Nrf2 in ACR-induced neurotoxicity including degeneration of monoaminergic axons and sensorimotor dysfunction. Male 10-week-old C57BL/6JJcl Nrf2-knockout mice and wild type (WT) counterparts were each divided into four groups of 12 and provided with drinking water containing acrylamide at 0, 67, 110 or 200 ppm for four weeks. The effects of acrylamide were examined by landing foot spread test, immunohistochemistry for noradrenaline (NA) and serotonin (5-HT)-containing axons and Iba1-positive microglia in the prefrontal cortex as well as quantitative real-time polymerase chain reaction (qRT-PCR) on antioxidant, proinflammatory and anti-inflammatory genes in the prefrontal cortex. Relative to the wild type, exposure of Nrf2-knockout mice to acrylamide increased hindlimb splay length, microglial area and process length as well as decreasing the density of NA and 5-HT-immunoreactive axons to a greater extent. Moreover, deletion of Nrf2 gene suppressed acrylamide-induced mRNA upregulation of Nrf2-antioxidants, NAD(P): quinone oxidoreductase 1 (NQO1), superoxide dismutase-1 (SOD-1) and heme oxygenase-1 (HO-1) as well as anti-inflammatory markers such as, arginase-1 (Arg1), found in the inflammatory zone-1 (Fizz1), chitinase-like 3 (Chi3l3), interleukin-4 receptor alpha (IL-4Rα), cluster of differentiation  206 (CD206) and transforming growth factor beta-1 (TGFβ1) while enhancing acrylamide-induced upregulation of pro-inflammatory cytokines, interleukin-1 beta (IL-1β), tumor necrosis-alpha (TNF-α) and inducible nitric oxide synthase (iNOS) in the prefrontal cortex. The results demonstrate susceptibility of mice lacking the Nrf2 gene to acrylamide-induced neurotoxicity and neuroinflammation with the activation of microglia. Moreover, the results suggest the role of Nrf2 not only in induction of antioxidant gene expression, but also in suppression of proinflammatory cytokine gene expression.
  • Masahiro Nakatochi, Yu Toyoda, Masahiro Kanai, Akiyoshi Nakayama, Yusuke Kawamura, Asahi Hishida, Haruo Mikami, Keitaro Matsuo, Toshiro Takezaki, Yukihide Momozawa, Yoichiro Kamatani, Sahoko Ichihara, Nariyoshi Shinomiya, Mitsuhiro Yokota, Kenji Wakai, Yukinori Okada, Hirotaka Matsuo
    Rheumatology (Oxford, England) 60(9) 4430-4432 2021年5月4日  
  • Yuki Kitamura, Nathan Mise, Yurie Mori, Yuka Suzuki, Tomoki Ohashi, Saeko Tada-Oikawa, Masaki Tokisu, Cai Zong, Shinji Oikawa, Sahoko Ichihara
    Scientific Reports 10(1) 2020年12月  
    <title>Abstract</title> Smoking increases the risk of cardiovascular diseases. The present study was designed to determine the effects of 2-month exposure to cigarette smoke (CS) on proteins in the left ventricles of spontaneously hypertensive rats (SHR) and to identify the molecular targets associated with the pathogenesis/progression of CS-induced cardiac hypertrophy. SHR and Wistar Kyoto rats (WKY) were exposed to CS at low (2 puffs/min for 40 min) or high dose (2 puffs/min for 120 min), 5 days a week for 2 months. Using the two-dimensional fluorescence difference gel electrophoresis combined with MALDI-TOF/TOF tandem mass spectrometry, we compared differences in the expression levels of proteins in the whole left ventricles induced by long-term smoking. High-dose CS mainly caused cardiac hypertrophy in SHR, but not WKY, but no change in blood pressure. Proteomic analysis identified 30 protein spots with significant alterations, with 14 up-regulated and 16 down-regulated proteins in the left ventricles of CS-exposed SHR, compared with control SHR. Among these proteins, two members of the heat shock proteins (HSP70 and HSP20) showed significant up-regulation in the left ventricles of CS high-dose SHR, and the results were confirmed by western blot analysis. Our findings suggested that HSPs play an important role in regulation of CS-induced cardiac hypertrophy.
  • Md. Shiblur Rahaman, Fozia Momotaz, Afrida Nurain, Protima Sarker, Sahoko Ichihara
    Present Environment and Sustainable Development 14(2) 151-162 2020年10月14日  
    Untreated wastewater disposal from industries has been a crucial environmental issue for developing countries like Bangladesh. The current study aims to investigate the status of Effluent Treatment Plant (ETP) and the quality of effluents in the Noakhali industrial area, Bangladesh. Total 10 industries were surveyed and the ETP status showed that about 30% of industries do not have ETP facilities and only 30% of industries use their ETP for the treatment of the effluents where the rest of the industry’s ETPs were under construction or exit but not used. Effluent samples were collected from seven locations near the discharge points of various industries. All the physicochemical parameters were determined using standard analytical procedures and analyzed the values comparing with the guideline standard by the Department of Environment (DoE), Bangladesh. The average values of electric conductivity (EC) have exceeded the tolerable limit in maximum effluent samples. On the contrary, the temperature, pH, and total dissolved solids (TDS) values were within the standard limit for all of the collected effluent samples. The chloride concentration of the three effluent samples surpassed the limit. The biological oxygen demand (BOD) and chemical oxygen demand (COD) limit were exceeded for the effluent sampling sites S-6 and S-7 collected near the food and beverage industry. Besides, the maximum dissolved oxygen (DO) values of the effluents were below the standard which indicates poor water quality. Environmental nuisance is producing in Noakhali industrial area as maximum industries have not enough wastewater treatment facilities. Present study demonstrated that it is obvious to operate the ETP regularly for improving the quality of effluents to save our native environment from the harmful effects of wastewater.
  • Yuka Suzuki, Gaku Ichihara, Satoshi Kawada, Kun'ichi Miyazawa, Tomoki Furutani, Arisa Hayashida, Eri Watanabe, Cai Zong, Lang Tran, Akihiko Ikegami, Sahoko Ichihara
    NanoImpact 20 100257-100257 2020年10月  
  • Cassandra N. Spracklen, Momoko Horikoshi, Young Jin Kim, Kuang Lin, Fiona Bragg, Sanghoon Moon, Ken Suzuki, Claudia H. T. Tam, Yasuharu Tabara, Soo-Heon Kwak, Fumihiko Takeuchi, Jirong Long, Victor J. Y. Lim, Jin-Fang Chai, Chien-Hsiun Chen, Masahiro Nakatochi, Jie Yao, Hyeok Sun Choi, Apoorva K. Iyengar, Hannah J. Perrin, Sarah M. Brotman, Martijn van de Bunt, Anna L. Gloyn, Jennifer E. Below, Michael Boehnke, Donald W. Bowden, John C. Chambers, Anubha Mahajan, Mark I. McCarthy, Maggie C. Y. Ng, Lauren E. Petty, Weihua Zhang, Andrew P. Morris, Linda S. Adair, Masato Akiyama, Zheng Bian, Juliana C. N. Chan, Li-Ching Chang, Miao-Li Chee, Yii-Der Ida Chen, Yuan-Tsong Chen, Zhengming Chen, Lee-Ming Chuang, Shufa Du, Penny Gordon-Larsen, Myron Gross, Xiuqing Guo, Yu Guo, Sohee Han, Annie-Green Howard, Wei Huang, Yi-Jen Hung, Mi Yeong Hwang, Chii-Min Hwu, Sahoko Ichihara, Masato Isono, Hye-Mi Jang, Guozhi Jiang, Jost B. Jonas, Yoichiro Kamatani, Tomohiro Katsuya, Takahisa Kawaguchi, Chiea-Chuen Khor, Katsuhiko Kohara, Myung-Shik Lee, Nanette R. Lee, Liming Li, Jianjun Liu, Andrea O. Luk, Jun Lv, Yukinori Okada, Mark A. Pereira, Charumathi Sabanayagam, Jinxiu Shi, Dong Mun Shin, Wing Yee So, Atsushi Takahashi, Brian Tomlinson, Fuu-Jen Tsai, Rob M. van Dam, Yong-Bing Xiang, Ken Yamamoto, Toshimasa Yamauchi, Kyungheon Yoon, Canqing Yu, Jian-Min Yuan, Liang Zhang, Wei Zheng, Michiya Igase, Yoon Shin Cho, Jerome I. Rotter, Ya-Xing Wang, Wayne H. H. Sheu, Mitsuhiro Yokota, Jer-Yuarn Wu, Ching-Yu Cheng, Tien-Yin Wong, Xiao-Ou Shu, Norihiro Kato, Kyong-Soo Park, E-Shyong Tai, Fumihiko Matsuda, Woon-Puay Koh, Ronald C. W. Ma, Shiro Maeda, Iona Y. Millwood, Juyoung Lee, Takashi Kadowaki, Robin G. Walters, Bong-Jo Kim, Karen L. Mohlke, Xueling Sim
    Nature 582(7811) 240-245 2020年6月  
  • Saeko Tada-Oikawa, Mana Eguchi, Michiko Yasuda, Kiyora Izuoka, Akihiko Ikegami, Sandra Vranic, Sonja Boland, Lang Tran, Gaku Ichihara, Sahoko Ichihara
    Chemical research in toxicology 2020年5月8日  査読有り
    Nanoparticles (NPs) are widely used in food, and analysis of their potential gastrointestinal toxicity is necessary. The present study was designed to determine the effects of silica dioxide (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) NPs on cultured THP-1 monocyte-derived macrophages and human epithelial colorectal adenocarcinoma (Caco-2) cells. Exposure to ZnO NPs for 24 h increased the production of redox response species (ROS) and reduced cell viability in a dose-dependent manner in THP-1 macrophages and Caco-2 cells. Although TiO2 and SiO2 NPs induced oxidative stress, they showed no apparent cytotoxicity against both cell types. The effects of functionalized SiO2 NPs on undifferentiated and differentiated Caco-2 cells were investigated using fluorescently labeled SiO2 NPs with neutral, positive, or negative surface charge. Exposure of both types of cells to the three kinds of SiO2 NPs significantly increased their interaction in a dose-dependent manner. The largest interaction with both types of cells was noted with exposure to more negatively surface-charged SiO2 NPs. Exposure to either positively or negatively, but not neutrally, surface-charged SiO2 NPs increased NO levels in differentiated Caco-2 cells. Exposure of differentiated Caco-2 cells to positively or negatively surface-charged SiO2 NPs also upregulated interleukin-8 expression. We conclude that functionalized surface-charged SiO2 NPs can induce pro-inflammatory responses but are noncytotoxic.
  • Lingyi Zhang, Satoshi Hara, Hiroshi Ichinose, Daichi Nagashima, Kyo Morita, Toshihiro Sakurai, Sahoko Ichihara, Gaku Ichihara
    Neurotoxicology 2020年3月5日  査読有り
    PURPOSE: Acrylamide is known to induce disorders in the central nervous system in humans and experimental animals. The present study investigated effects of exposure to acrylamide on adult neurogenesis, noradrenergic axons and the level of norepinephrine in the brain of male rats. METHOD: Four groups of 12 male Wistar rats each were exposed to acrylamide at 0, 0.2, 2 and 20 mg/kg body weight by gavage for 5 weeks. Six rats of each groups were injected with 5-bromo-2'-deoxy-uridine (BrdU) after five-week exposure to acrylamide to examine proliferative cells in the dentate gyrus using immunostaining. Density of noradrenergic and serotonergic axons in the prefrontal cortex, hippocampus and cortex behind the bregma was quantified. Remaining 6 rats were decapitated after the last exposure and brains were dissected out to measure monoamine level in the hippocampus and prefrontal cortex using high performance liquid chromatography. RESULT: Exposure to acrylamide dose-dependently decreased the density of noradrenergic axons in the prefrontal cortex with a significant change at 20 mg/kg. Norepinephrine level decreased in the hippocampus at 20 mg/kg. Exposure to acrylamide at 20 mg/kg or less did not change the number of BrdU positive cells, but the result should be considered preliminary. CONCLUSION: The results show that oral exposure to acrylamide induces decrease in noradrenergic axons and norepinephrine level in the brain of rats. Given the similar effects are observed in 1-bromopropane-exposed rats, there may be the common mechanism in the toxicity of soft electrophiles to the central nervous system.
  • Frederick Adams EKUBAN, 宗 才, 瀧川 円賀, 森川 浩太, 櫻井 敏博, 市原 佐保子, 伊東 健, 山本 雅之, 大迫 誠一郎, 市原 学
    日本毒性学会学術年会 47.1 P-28E 2020年  
    Acrylamide (ACR) is an electrophile which has been used extensively in industry and is also formed unintentionally in food substances cooked or processed at high temperatures, such as potato chips or coffee through Maillard reaction. Acrylamide has been recognized as a potent neurotoxin which is known to cause neuropathy or encephalopathy in humans and experimental animals. As a measure of protection against neurotoxicity, the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) has been identified to be a master regulator of the cellular defense system which activates antioxidant and cytoprotective genes. However, knowledge about mechanistic roles of Nrf2 in acrylamide-induced neurotoxicity remains poorly understood. This study therefore sought to investigate and clarify the roles of Nrf2 in ACR-induced neurotoxicity. Forty-eight male Nrf2-knockout (Nrf2-KO) mice from the C57BL/6JJcl background, aged 10-weeks together with their age and sex-matched wild-type (WT) counterparts were each divided into four groups of twelve and daily exposed to ACR at 0, 67, 110 or 200 ppm in drinking water for 28 days. Following exposure of mice to ACR, Landing Foot spread test, an assessment of motor function and a major endpoint marker of neurotoxicity as well as immunohistochemistry for noradrenaline transporter (NAT) and serotonin transporter (SERT) antibody in the dorsal and ventral medial prefrontal cortex were performed. Nrf2-KO mice showed exacerbated impairment of motor functions evidenced by the increased hindlimb splay relative to WT mice at the same exposure levels. Immunohistochemistry results showed severe degeneration of both noradrenergic and serotonergic axons characterized by a dose-dependent decrease in the density of immunoreactive axons in Nrf2-KO mice relative to WT mice. Moreover, body weight, whole brain weight and cerebellum weight were significantly reduced in Nrf2-KO mice compared to the WT mice. The results suggest increased susceptibility to ACR-induced neurotoxicity in mice lacking the Nrf2 gene. In conclusion, Nrf2 is able to attenuate the effects of ACR-induced neurotoxicity in mice and thus remains a crucial target for the preventive modulation of neurotoxicity.
  • Radwa Sehsah, Wenting Wu, Sahoko Ichihara, Naozumi Hashimoto, Yoshinori Hasegawa, Cai Zong, Ken Itoh, Masayuki Yamamoto, Ahmed Ali Elsayed, Soheir El-Bestar, Emily Kamel, Gaku Ichihara
    Particle and fibre toxicology 16(1) 47-47 2019年12月16日  査読有り
    BACKGROUND: Zinc oxide nanoparticles (ZnO-NPs) are widely used in many industrial sectors and previous studies have reported that exposure of the lungs to ZnO-NPs induces both acute and/or chronic pulmonary inflammation, but the exact mechanism underlying such response remains elusive. This study investigated the role of nuclear factor-erythroid 2-related factor (Nrf2) in pulmonary inflammation induced by exposure to ZnO-NPs using Nrf2 null (Nrf2-/-) mice. METHODS: Twenty-four male Nrf2-/- mice and thirty male wild type C57BL/6 J mice were divided into three groups of eight and ten each respectively, and exposed once to ZnO-NPs at 0, 10, 30 μg/mouse by pharyngeal aspiration. At 14 days after the exposure to ZnO-NPs, bronchoalveolar lavage fluid (BALF) and lungs were collected to quantify protein level and the number of inflammatory cells. The mRNA levels of Nrf2-dependent antioxidant enzymes and inflammatory cytokines in lung tissue were measured. RESULTS: Exposure to ZnO-NPs dose-dependently increased the number of total cells, macrophages, lymphocytes and eosinophils in BALF both in Nrf2-/- mice and wild type mice, but the magnitude of increase was significantly higher in Nrf2-/- mice than wild type mice. The number of neutrophils in BALF increased in Nrf2-/- mice, being accompanied by marginal trend of increase in mRNA expression of MIP-2, neutrophil chemoattractant, but such changes were not observed in wild type mice. Exposure to ZnO-NPs did not dose-dependently increase mRNA level of Nrf2-dependent antioxidant enzymes both in Nrf2-/- mice and wild type mice. CONCLUSION: Pharyngeal aspiration of ZnO-NPs induced infiltration of inflammatory cells in the lung of mice, but minimally induced Nrf2-dependent antioxidant enzymes. The results suggest that Nrf2 play a role in negative regulation on ZnO-NP exposure-induced neutrophil migration, but does not demonstrate that the regulation is through suppression of oxidative stress.
  • Yusuke Kawamura, Hirofumi Nakaoka, Akiyoshi Nakayama, Yukinori Okada, Ken Yamamoto, Toshihide Higashino, Masayuki Sakiyama, Toru Shimizu, Hiroshi Ooyama, Keiko Ooyama, Mitsuo Nagase, Yuji Hidaka, Yuko Shirahama, Kazuyoshi Hosomichi, Yuichiro Nishida, Ippei Shimoshikiryo, Asahi Hishida, Sakurako Katsuura-Kamano, Seiko Shimizu, Makoto Kawaguchi, Hirokazu Uemura, Rie Ibusuki, Megumi Hara, Mariko Naito, Mikiya Takao, Mayuko Nakajima, Satoko Iwasawa, Hiroshi Nakashima, Keizo Ohnaka, Takahiro Nakamura, Blanka Stiburkova, Tony R Merriman, Masahiro Nakatochi, Sahoko Ichihara, Mitsuhiro Yokota, Tappei Takada, Tatsuya Saitoh, Yoichiro Kamatani, Atsushi Takahashi, Kokichi Arisawa, Toshiro Takezaki, Keitaro Tanaka, Kenji Wakai, Michiaki Kubo, Tatsuo Hosoya, Kimiyoshi Ichida, Ituro Inoue, Nariyoshi Shinomiya, Hirotaka Matsuo
    Annals of the rheumatic diseases 78(10) 1430-1437 2019年10月  査読有り
    OBJECTIVE: The first ever genome-wide association study (GWAS) of clinically defined gout cases and asymptomatic hyperuricaemia (AHUA) controls was performed to identify novel gout loci that aggravate AHUA into gout. METHODS: We carried out a GWAS of 945 clinically defined gout cases and 1003 AHUA controls followed by 2 replication studies. In total, 2860 gout cases and 3149 AHUA controls (all Japanese men) were analysed. We also compared the ORs for each locus in the present GWAS (gout vs AHUA) with those in the previous GWAS (gout vs normouricaemia). RESULTS: This new approach enabled us to identify two novel gout loci (rs7927466 of CNTN5 and rs9952962 of MIR302F) and one suggestive locus (rs12980365 of ZNF724) at the genome-wide significance level (p<5.0×10-8). The present study also identified the loci of ABCG2, ALDH2 and SLC2A9. One of them, rs671 of ALDH2, was identified as a gout locus by GWAS for the first time. Comparing ORs for each locus in the present versus the previous GWAS revealed three 'gout vs AHUA GWAS'-specific loci (CNTN5, MIR302F and ZNF724) to be clearly associated with mechanisms of gout development which distinctly differ from the known gout risk loci that basically elevate serum uric acid level. CONCLUSIONS: This meta-analysis is the first to reveal the loci associated with crystal-induced inflammation, the last step in gout development that aggravates AHUA into gout. Our findings should help to elucidate the molecular mechanisms of gout development and assist the prevention of gout attacks in high-risk AHUA individuals.
  • Vignesh Sundararajan, Pallavi Dan, Ajay Kumar, G. Devana, Venkatasubbu, Sahoko Ichihara, Gaku Ichihara, Sahabudeen Sheik Mohideen
    APPL SURF SCI 490 70-80 2019年10月1日  査読有り
  • Pallavi Dan, Vignesh Sundararajan, Harsana Ganeshkumar, Barathan Gnanabarathi, Arun Kumar Subramanian, G. Devanand Venkatasubu, Sahoko Ichihara, Gaku Ichihara, Sahabudeen Sheik Mohideen
    Applied Surface Science 484 568-577 2019年8月1日  査読有り
    © 2019 Elsevier B.V. Hydroxyapatite (HAp), a compound similar in composition to human hard tissues such as bone and teeth, has widespread applications in bulk as well as nanoparticle form in numerous fields due to excellent biocompatibility and stability. The increased use of this nanoparticle thus warrants the study of its toxic potential in in vivo models. In this study, the toxicity induced by HAp NPs administered via the oral route using Drosophila as an in vivo model was investigated. Biochemical assays such as lipid peroxidation and nitro blue tetrazolium assay did not reveal toxicity at lowest (10 μg/ml) as well as highest (1000 μg/ml) doses. The HAp nanoparticle-treated flies and larvae did not exhibit signs of behavioral change as evidenced from the negative geotaxis assay and larvae crawling assay, respectively. Survival assay to assess the chronic toxicity of HAp nanoparticles also did not reveal any signs of toxicity at both lowest and highest doses. This demonstrates that hydroxyapatite nanoparticles do not elicit significant in vivo toxicity. Considering the paucity of studies available to support the non-toxic effect of HAp nanoparticles, further investigations are warranted in Drosophila and other in vivo models. Moreover, such HAp nanoparticles can also serve as reliable carrier for drug delivery system.
  • Daichi Nagashima, Lingyi Zhang, Yuki Kitamura, Sahoko Ichihara, Eri Watanabe, Cai Zong, Yuko Yamano, Toshihiro Sakurai, Shinji Oikawa, Gaku Ichihara
    Archives of toxicology 93(7) 1993-2006 2019年7月  査読有り
    Acrylamide has been used industrially and also found in certain foods cooked at high temperatures. Previous reports described acrylamide-related human intoxication who presented with ataxia, memory impairment, and/or illusion. The aim of this study was to characterize the molecular mechanisms of neurotoxicity of acrylamide by analyzing the expression levels of various proteins in the hippocampus of rats exposed to acrylamide. Male Wistar rats were administered acrylamide by gavage at 0, 2, and 20 mg/kg for 1 week or 0, 0.2, 2, and 20 mg/kg for 5 weeks. At the end of the experiment, the hippocampus was dissected out and proteins were extracted for two-dimensional difference gel electrophoresis combined with matrix-assisted laser-desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF/MS). MALDI-TOF/TOF/MS identified significant changes in two proteins in the 1-week and 22 proteins in the 5-week exposure groups. These changes were up-regulation in 9 and down-regulation in 13 proteins in the hippocampus of rats exposed to acrylamide at 20 mg/kg for 5 weeks. PANTHER overrepresentation test based on the GO of biological process showed significant overrepresentation in proteins annotated to nicotinamide nucleotide metabolic process, coenzyme biosynthetic process, pyruvate metabolic process, and carbohydrate metabolic process. The test also showed significant overrepresentation in proteins annotated to creatinine kinase activity for the GO of molecular function as well as myelin sheath, cytoplasmic part, and cell body for the GO of cellular component. Comparison with a previous proteomic study on hippocampal proteins in rats exposed to 1-bromopropane identified triosephosphate isomerase, mitochondrial creatine kinase U-type, creatine kinase β-type and proteasome subunit α type-1 as proteins affected by exposure to acrylamide and 1-bromopropane, suggesting a common mechanism of neurotoxicity for soft electrophiles.
  • Cai Zong, Rieka Hasegawa, Makoto Urushitani, Lingyi Zhang, Daichi Nagashima, Toshihiro Sakurai, Sahoko Ichihara, Seiichiroh Ohsako, Gaku Ichihara
    Archives of toxicology 93(7) 2007-2019 2019年7月  査読有り
    Acrylamide, a soft electrophile, is widely used in the industry and laboratories, and also contaminates certain foods. Neurotoxicity and neurodegenerative effects of acrylamide have been reported in humans and experimental animals, although the underlying mechanism remains obscure. Activation of microglia and neuroinflammation has been demonstrated in various neurodegenerative diseases as well as other pathologies of the brain. The present study aimed to investigate the role of microglial activation and neuroinflammation in acrylamide neurotoxicity. Male 10-week-old Wistar rats were exposed to acrylamide by gavage at 0, 0.2, 2, or 20 mg/kg BW, once per day for 5 weeks. The results showed that 5-week exposure to acrylamide induced inflammatory responses in the cerebral cortex, evident by upregulated mRNA and protein expression of pro-inflammatory cytokines IL-1β, IL-6, and IL-18. Acrylamide also induced activation of microglia, indicated by increased expression of microglial markers, CD11b and CD40, and increased CD11b/c-positive microglial area and microglial process length. In vitro studies using BV-2 microglial cells confirmed microglial inflammatory response, as evident by time- (0-36 h; 50 μM) and dose- (0-500 μM; 24 h) dependent increase in mRNA expression of IL-1β and IL-18, as well as the inflammatory marker iNOS. Furthermore, acrylamide-induced upregulation of pro-inflammatory cytokines was mediated through the NLRP3 inflammasome pathway, as evident by increased expression of NLRP3, caspase 1, and ASC in the rat cerebral cortex, and by the inhibitory effects of NLRP3 inflammasome inhibitor on the acrylamide-induced upregulation of NLRP3, caspase 1, IL-1β, and IL-18 in BV-2 microglia.
  • Michael Riediker, Daniele Zink, Wolfgang Kreyling, Günter Oberdörster, Alison Elder, Uschi Graham, Iseult Lynch, Albert Duschl, Gaku Ichihara, Sahoko Ichihara, Takahiro Kobayashi, Naomi Hisanaga, Masakazu Umezawa, Tsun-Jen Cheng, Richard Handy, Mary Gulumian, Sally Tinkle, Flemming Cassee
    Particle and fibre toxicology 16(1) 26-26 2019年6月27日  査読有り
    After the publication of this article [1] it was hihglighted that the number of deaths related to natural disasters was incorrectly reported in the second paragraph of the Hazards from Natural particulates and the evolution of the biosphere section. This correction article shows the correct and incorrect statement. This correction does not change the idea presented in the article that from an evolutionary view point, natural disasters account only for a small fraction of the people on the planet. The original article has been updated.
  • 滝澤 亮哉, 宗 才, 木下 和生, 櫻井 敏博, 市原 佐保子, 市原 学
    The Journal of Toxicological Sciences 44(Suppl.) S223-S223 2019年6月  
  • Ichihara S, Li P, Mise N, Suzuki Y, Izuoka K, Nakajima T, Gonzalez F, Ichihara G
    ARCH TOXICOL 93(6) 1543-1553 2019年6月  査読有り
  • Michael Riediker, Daniele Zink, Wolfgang Kreyling, Günter Oberdörster, Alison Elder, Uschi Graham, Iseult Lynch, Albert Duschl, Gaku Ichihara, Sahoko Ichihara, Takahiro Kobayashi, Naomi Hisanaga, Masakazu Umezawa, Tsun-Jen Cheng, Richard Handy, Mary Gulumian, Sally Tinkle, Flemming Cassee
    Particle and fibre toxicology 16(1) 19-19 2019年4月23日  査読有り
    BACKGROUND: Particles and fibres affect human health as a function of their properties such as chemical composition, size and shape but also depending on complex interactions in an organism that occur at various levels between particle uptake and target organ responses. While particulate pollution is one of the leading contributors to the global burden of disease, particles are also increasingly used for medical purposes. Over the past decades we have gained considerable experience in how particle properties and particle-bio interactions are linked to human health. This insight is useful for improved risk management in the case of unwanted health effects but also for developing novel medical therapies. The concepts that help us better understand particles' and fibres' risks include the fate of particles in the body; exposure, dosimetry and dose-metrics and the 5 Bs: bioavailability, biopersistence, bioprocessing, biomodification and bioclearance of (nano)particles. This includes the role of the biomolecule corona, immunity and systemic responses, non-specific effects in the lungs and other body parts, particle effects and the developing body, and the link from the natural environment to human health. The importance of these different concepts for the human health risk depends not only on the properties of the particles and fibres, but is also strongly influenced by production, use and disposal scenarios. CONCLUSIONS: Lessons learned from the past can prove helpful for the future of the field, notably for understanding novel particles and fibres and for defining appropriate risk management and governance approaches.
  • Masahiro Nakatochi, Masahiro Kanai, Akiyoshi Nakayama, Asahi Hishida, Yusuke Kawamura, Sahoko Ichihara, Masato Akiyama, Hiroaki Ikezaki, Norihiro Furusyo, Seiko Shimizu, Ken Yamamoto, Makoto Hirata, Rieko Okada, Sayo Kawai, Makoto Kawaguchi, Yuichiro Nishida, Chisato Shimanoe, Rie Ibusuki, Toshiro Takezaki, Mayuko Nakajima, Mikiya Takao, Etsuko Ozaki, Daisuke Matsui, Takeshi Nishiyama, Sadao Suzuki, Naoyuki Takashima, Yoshikuni Kita, Kaori Endoh, Kiyonori Kuriki, Hirokazu Uemura, Kokichi Arisawa, Isao Oze, Keitaro Matsuo, Yohko Nakamura, Haruo Mikami, Takashi Tamura, Hiroshi Nakashima, Takahiro Nakamura, Norihiro Kato, Koichi Matsuda, Yoshinori Murakami, Tatsuaki Matsubara, Mariko Naito, Michiaki Kubo, Yoichiro Kamatani, Nariyoshi Shinomiya, Mitsuhiro Yokota, Kenji Wakai, Yukinori Okada, Hirotaka Matsuo
    Communications Biology 2019年4月8日  査読有り
    &lt;5 × 10
  • Vranic S, Shimada Y, Ichihara S, Kimata M, Wu W, Tanaka T, Boland S, Tran L, Ichihara G
    International journal of molecular sciences 20(4) 2019年2月18日  査読有り
  • 宗 才, 岩間 聖, 山村 征寛, 漆谷 真, 櫻井 敏博, 市原 佐保子, 大迫 誠一郎, 市原 学
    日本毒性学会学術年会 46.1 P-1E 2019年  
    [Background] Acrylamide exhibits neurotoxicity in humans and experimental animals. Our previous study revealed that exposure to acrylamide induced specific decrease in norepinephrine level and density of noradrenergic axons in rat brain, although the underling mechanism remains obscure. This study aims to investigate role of microglia and autophagy pathway in neurotoxicity of acrylamide. [Methods] In vivo: Six groups (n=3) of C57BL/6J mice were exposed to single dose of acrylamide by oral gavage at 20 mg/kg BW or vehicle, and were perfused through ascending aorta 1, 3, or 6 h after exposure. Induction of autophagy was investigated by immunostaining of LC3B. In vitro: CATH.a catecholaminergic neuronal cells or BV-2 microglial cells were mono-cultured or co-cultured through directly mixing or using insert, and then exposed to acrylamide (0, 0.1, 0.5, 1, 2 mM; 24 h). Cell viability, cytotoxicity, ATP production, caspase-3/7 activity, apoptosis, and expression of autophagy marker LC3B were measured. [Results] LC3B positive neuronal cell bodies were observed in the cerebellum of mice brain, at 1 or 3 hrs after acrylamide exposure. Exposure to acrylamide at 2mM significantly decreased cell viability and ATP production in CATH.a neuronal cells, although LDH release was not changed. Exposure to acrylamide at 1 or 2 mM significantly decreased caspase-3/7 activity in CATH.a cells. Caspase-3/7 activity was dose-dependently increased in CATH.a cells by autophagy inhibitor chloroquine. However, the ratio of LC3-II/LC3-I showed no change in CATH.a cells after acrylamide exposure. Exposure to acrylamide at 2 mM also decreased cell viability, and increased LDH release and caspase-3/7 activity, in BV-2 microglial cells. Moreover, acrylamide exposure at 1 mM, significantly decreased cell viability, and increased LDH release. [Conclusion] Compared to mono-culture, co-culture of CATH.a neuronal cells with BV-2 microglial cells may exacerbate the cytotoxicity of acrylamide. The in vivo results also suggested involvement of autophagy in neurotoxicity of acrylamide, but further studies are needed to reveal it.
  • Fumihiko Takeuchi, Masato Akiyama, Nana Matoba, Tomohiro Katsuya, Masahiro Nakatochi, Yasuharu Tabara, Akira Narita, Woei-Yuh Saw, Sanghoon Moon, Cassandra N Spracklen, Jin-Fang Chai, Young-Jin Kim, Liang Zhang, Chaolong Wang, Huaixing Li, Honglan Li, Jer-Yuarn Wu, Rajkumar Dorajoo, Jovia L Nierenberg, Ya Xing Wang, Jing He, Derrick A Bennett, Atsushi Takahashi, Yukihide Momozawa, Makoto Hirata, Koichi Matsuda, Hiromi Rakugi, Eitaro Nakashima, Masato Isono, Matsuyuki Shirota, Atsushi Hozawa, Sahoko Ichihara, Tatsuaki Matsubara, Ken Yamamoto, Katsuhiko Kohara, Michiya Igase, Sohee Han, Penny Gordon-Larsen, Wei Huang, Nanette R Lee, Linda S Adair, Mi Yeong Hwang, Juyoung Lee, Miao Li Chee, Charumathi Sabanayagam, Wanting Zhao, Jianjun Liu, Dermot F Reilly, Liang Sun, Shaofeng Huo, Todd L Edwards, Jirong Long, Li-Ching Chang, Chien-Hsiun Chen, Jian-Min Yuan, Woon-Puay Koh, Yechiel Friedlander, Tanika N Kelly, Wen Bin Wei, Liang Xu, Hui Cai, Yong-Bing Xiang, Kuang Lin, Robert Clarke, Robin G Walters, Iona Y Millwood, Liming Li, John C Chambers, Jaspal S Kooner, Paul Elliott, Pim van der Harst, Zhengming Chen, Makoto Sasaki, Xiao-Ou Shu, Jost B Jonas, Jiang He, Chew-Kiat Heng, Yuan-Tsong Chen, Wei Zheng, Xu Lin, Yik-Ying Teo, E-Shyong Tai, Ching-Yu Cheng, Tien Yin Wong, Xueling Sim, Karen L Mohlke, Masayuki Yamamoto, Bong-Jo Kim, Tetsuro Miki, Toru Nabika, Mitsuhiro Yokota, Yoichiro Kamatani, Michiaki Kubo, Norihiro Kato
    Nature communications 9(1) 5052-5052 2018年11月28日  査読有り
    Blood pressure (BP) is a major risk factor for cardiovascular disease and more than 200 genetic loci associated with BP are known. Here, we perform a multi-stage genome-wide association study for BP (max N = 289,038) principally in East Asians and meta-analysis in East Asians and Europeans. We report 19 new genetic loci and ancestry-specific BP variants, conforming to a common ancestry-specific variant association model. At 10 unique loci, distinct non-rare ancestry-specific variants colocalize within the same linkage disequilibrium block despite the significantly discordant effects for the proxy shared variants between the ethnic groups. The genome-wide transethnic correlation of causal-variant effect-sizes is 0.898 and 0.851 for systolic and diastolic BP, respectively. Some of the ancestry-specific association signals are also influenced by a selective sweep. Our results provide new evidence for the role of common ancestry-specific variants and natural selection in ethnic differences in complex traits such as BP.
  • Fukatsu H, Koide N, Tada-Oikawa S, Izuoka K, Ikegami A, Ichihara S, Ukaji T, Morita N, Naiki Y, Komatsu T, Umezawa K
    Molecular medicine reports 18(6) 5279-5285 2018年10月  査読有り
  • Kitamura Y, Kojima M, Kurosawa T, Sasaki R, Ichihara S, Hiraku Y, Tomimoto H, Murata M, Oikawa S
    Neuroscience 392 121-128 2018年9月  査読有り
  • Guoliang Li, Lihong Liang, Jingchao Yang, Lihai Zeng, Zhiwei Xie, Yizhou Zhong, Xiaolin Ruan, Ming Dong, Zhanhong Yang, Guanchao Lai, Weixin Huang, Aichu Yang, Jiabing Chen, Banghua Wu, Huaming Xu, Dezhi Meng, Shijie Hu, Lihua Xia, Xingfen Yang, Laiyu Li, Sahoko Ichihara, Gaku Ichihara, Hanlin Huang, Zhenlie Huang
    Nanotoxicology 12(6) 571-585 2018年8月  査読有り
    Calcium carbonate nanomaterials (nano-CaCO3) are widely used in both manufacturing and consumer products, but their potential health hazards remain unclear. The objective of this study was to survey workplace exposure levels and health effects of workers exposed to nano-CaCO3. Personal and area sampling, as well as real-time and dust monitoring, were performed to characterize mass exposure, particle size distribution, and particle number exposure. A total of 56 workers (28 exposed workers and 28 unexposed controls) were studied in a cross-sectional study. They completed physical examinations, spirometry, and digital radiography. The results showed that the gravimetric nano-CaCO3 concentration was 5.264 ± 6.987 mg/m3 (0.037-22.192 mg/m3) at the workplace, and 3.577 ± 2.065 mg/m3 (2.042-8.161 mg/m3) in the breathing zone of the exposed workers. The particle number concentrations ranged from 8193 to 39 621 particles/cm3 with a size range of 30-150 nm. The process of packing had the highest gravimetric and particle number concentrations. The particle number concentration positively correlated with gravimetric concentrations of nano-CaCO3. The levels of hemoglobin, creatine phosphokinase (CK), lactate dehydrogenase, and high-density lipoprotein cholesterol (HDL-C) in the nano-CaCO3 exposure group increased significantly, but the white blood cell count (WBC), Complement 3 (C3), total protein (TP), uric acid, and creatinine (CREA) all decreased significantly. The prevalence rate of pulmonary hypofunction was significantly higher (p = 0.037), and the levels of vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, peak expiratory flow and forced expiratory flow 25% (FEF 25%), FEF 25-75% were negatively correlated with gravimetric concentrations of nano-CaCO3 (p < 0.05). Logistic analysis showed that nano-CaCO3 exposure level was associated with pulmonary hypofunction (p = 0.005). Meanwhile, a dose-effect relationship was found between the accumulated gravimetric concentrations of nano-CaCO3 and the prevalence rate of pulmonary hypofunction (p = 0.048). In conclusion, long-term and high-level nano-CaCO3 exposure can induce pulmonary hypofunction in workers. Thus, lung function examination is suggested for occupational populations with nano-CaCO3 exposure. Furthermore, future health protection efforts should focus on senior workers with accumulation effects of nano-CaCO3 exposure.
  • Yuka Yokoyama, Nathan Mise, Yuka Suzuki, Saeko Tada-Oikawa, Kiyora Izuoka, Lingyi Zhang, Cai Zong, Akira Takai, Yoshiji Yamada, Sahoko Ichihara
    International Journal of Molecular Sciences 19(4) 2018年4月6日  査読有り
    Smoking increases the risk of atherosclerosis-related events, such as myocardial infarction and ischemic stroke. Recent studies have examined the expression levels of altered microRNAs (miRNAs) in various diseases. The profiles of tissue miRNAs can be potentially used in diagnosis or prognosis. However, there are limited studies on miRNAs following exposure to cigarette smoke (CS). The present study was designed to dissect the effects and cellular/molecular mechanisms of CS-induced atherosclerogenesis. Apolipoprotein E knockout (ApoE KO) mice were exposed to CS for five days a week for two months at low (two puffs/min for 40 min/day) or high dose (two puffs/min for 120 min/day). We measured the area of atherosclerotic plaques in the aorta, representing the expression of miRNAs after the exposure period. Two-month exposure to the high dose of CS significantly increased the plaque area in aortic arch, and significantly upregulated the expression of atherosclerotic markers (VCAM-1, ICAM-1, MCP1, p22phox, and gp91phox). Exposure to the high dose of CS also significantly upregulated the miRNA-155 level in the aortic tissues of ApoE KO mice. Moreover, the expression level of miR-126 tended to be downregulated and that of miR-21 tended to be upregulated in ApoE KO mice exposed to the high dose of CS, albeit statistically insignificant. The results suggest that CS induces atherosclerosis through increased vascular inflammation and NADPH oxidase expression and also emphasize the importance of miRNAs in the pathogenesis of CS-induced atherosclerosis. Our findings provide evidence for miRNAs as potential mediators of inflammation and atherosclerosis induced by CS.
  • Kentaro Kuzuya, Sahoko Ichihara, Yuka Suzuki, Chisa Inoue, Gaku Ichihara, Syota Kurimoto, Shinji Oikawa
    PloS one 13(2) e0192624 2018年  査読有り
    Given the hypothesis that inflammation plays a critical role in the progression of cardiovascular diseases, the aim of the present study was to identify new diagnostic and prognostic biomarkers of myocardial proteins involved in early-phase cardiac impairment, using proteomics analysis. Using the two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with MALDI-TOF/TOF tandem mass spectrometry, we compared differences in the expression of proteins in the whole left ventricles between control hamsters, dilated cardiomyopathic hamsters (TO-2), and hypertrophy cardiomyopathic hamsters (Bio14.6) at 6 weeks of age (n = 6, each group). Proteomic analysis identified 10 protein spots with significant alterations, with 7 up-regulated and 3 down-regulated proteins in the left ventricles of both TO-2 and Bio 14.6 hamsters, compared with control hamsters. Of the total alterations, peroxiredoxin 2 (PRDX2) showed significant upregulation in the left ventricles of TO-2 and Bio 14.6 hamsters. Our data suggest that PRDX2, a redox regulating molecule, is involved in early-phase left ventricular impairment in hamsters with cardiomyopathy.
  • Fumihiko Takeuchi, Tomohiro Katsuya, Ryosuke Kimura, Toru Nabika, Minoru Isomura, Takayoshi Ohkubo, Yasuharu Tabara, Ken Yamamoto, Mitsuhiro Yokota, Xuanyao Liu, Xuanyao Liu, Woei Yuh Saw, Woei Yuh Saw, Dolikun Mamatyusupu, Wenjun Yang, Shuhua Xu, Shuhua Xu, Shuhua Xu, Yik Ying Teo, Yik Ying Teo, Yik Ying Teo, Yik Ying Teo, Yik Ying Teo, Yik Ying Teo, Norihiro Kato, Koichi Akiyama, Hiroyuki Asano, Kei Asayama, Toshikazu Haga, Azusa Hara, Takuo Hirose, Miki Hosaka, Sahoko Ichihara, Yutaka Imai, Ryusuke Inoue, Aya Ishi-guro, Minoru Isomura, Masato Isono, Kei Kamide, Norihiro Kato, Tomohiro Katsuya, Masahiro Kikuya, Katsuhiko Kohara, Tatsuaki Matsubara, Ayako Matsuda, Hirohito Metoki, Tetsuro Miki, Tetsuro Miki, Keiko Murakami, Toru Nabika, Masahiro Nakatochi, Toshio Ogihara, Keizo Ohnaka, Takayoshi Ohkubo, Hiromi Rakugi, Michihiro Satoh, Kuni hiro Shiwaku, Ken Sugimoto, Yasuharu Tabara, Yoichi Takami, Ryoichi Takayanagi, Fumihiko Takeuchi, Megumi Tsubota-Utsugi, Ken Yamamoto, Koichi Yamamoto, Masayuki Yamasaki, Daisaku Yasui, Mitsuhiro Yokota
    PLoS ONE 12 2017年11月1日  
    © 2017 Takeuchi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The contemporary Japanese populations largely consist of three genetically distinct groups —Hondo, Ryukyu and Ainu. By principal-component analysis, while the three groups can be clearly separated, the Hondo people, comprising 99% of the Japanese, form one almost indistinguishable cluster. To understand fine-scale genetic structure, we applied powerful haplotype-based statistical methods to genome-wide single nucleotide polymorphism data from 1600 Japanese individuals, sampled from eight distinct regions in Japan. We then combined the Japanese data with 26 other Asian populations data to analyze the shared ancestry and genetic differentiation. We found that the Japanese could be separated into nine genetic clusters in our dataset, showing a marked concordance with geography; and that major components of ancestry profile of Japanese were from the Korean and Han Chinese clusters. We also detected and dated admixture in the Japanese. While genetic differentiation between Ryukyu and Hondo was suggested to be caused in part by positive selection, genetic differentiation among the Hondo clusters appeared to result principally from genetic drift. Notably, in Asians, we found the possibility that positive selection accentuated genetic differentiation among distant populations but attenuated genetic differentiation among close populations. These findings are significant for studies of human evolution and medical genetics.
  • Sahoko Ichihara, Yuka Suzuki, Jie Chang, Kentaro Kuzuya, Chisa Inoue, Yuki Kitamura, Shinji Oikawa
    SCIENTIFIC REPORTS 7(1) 9243 2017年8月  査読有り
    Inflammation enhanced by accumulation of reactive oxygen species plays an essential role in the progression of cardiovascular diseases. Using the 2D-oxyblot analysis and 2D-difference image gel electrophoresis (2D-DIGE), we compared the levels of ROS-induced carbonyl modification of myocardial proteins in the whole left ventricles between 6-week-old hamsters with dilated (TO-2) and hypertrophic cardiomyopathy (Bio14.6) and control hamsters (F1B). Then, 2D electrophoresis combined with MALDI-TOF/TOF tandem mass spectrometry detected 18 proteins with increased carbonyl level in cardiomyopathy hamsters compared with control hamster. Carbonyl modification of proteins related to ATP synthesis, including citric acid cycle and electron transport system, was observed in the hearts of hamsters with both types of cardiomyopathy. Further analysis indicated that left ventricular carbonyl production correlated negatively with succinyl-CoA:3-ketoacid-coenzyme A transferase 1 activity (r(2) = 0.60, P = 0.0007) and ATP concentration (r(2) = 0.29, P = 0.037), suggesting that protein carbonylation has negative effects on the levels of these biomolecules. Furthermore, carbonyl production significantly correlated with plasma Troponin T level (r(2) = 0.33, P = 0.026). Reduction of energy metabolism by oxidative damage may contribute to the development of left ventricular impairment in cardiomyopathy.
  • Masahiro Nakatochi, Sahoko Ichihara, Ken Yamamoto, Keiko Naruse, Shigeki Yokota, Hiroyuki Asano, Tatsuaki Matsubara, Mitsuhiro Yokota
    Clinical Epigenetics 9(1) 54 2017年5月15日  査読有り
    Background: Development of cardiovascular disease (CVD), including coronary artery disease, arrhythmia, and ischemic stroke, depends on environmental and genetic factors. To investigate the epigenetic basis of myocardial infarction (MI), we performed an epigenome-wide association study for this condition in elderly Japanese subjects. A total of 192 case subjects with MI and 192 control subjects were recruited from hospital attendees and the general population, respectively. Genome-wide DNA methylation (DNAm) profiles for DNA isolated from whole blood were obtained by analysis with an Infinium HumanMethylation450 BeadChip. The relation of DNAm sites found to be significantly associated with MI to nearby single nucleotide polymorphisms (SNPs) previously shown to be associated with CVD was assessed in the control group. Findings: Three DNAm sites (cg06642177, cg07786668, cg17218495) showed genome-wide significant associations with MI (p = 4.33 × 10−8, 3.96 × 10−10, and 3.77 × 10−8, respectively). Two of these sites (cg07786668, cg17218495) still showed such associations after adjustment for classical risk factors of MI (p = 1.04 × 10−7 and 6.60 × 10−8, respectively). The DNAm sites cg07786668 and cg17218495 are located in ZFHX3 (zinc finger homeobox 3) and SMARCA4 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4) genes, respectively. SNPs in ZFHX3 or SMARCA4 that were previously found to be associated with CVD were not significantly associated with these DNAm sites in our control subjects. Conclusions: We identified two DNAm sites—cg07786668 in ZFHX3 and cg17218495 in SMARCA4— that are independently and significantly associated with MI. Our results suggest that the development of MI might be influenced by changes in DNAm at these sites via a pathway that differs from that affected by CVD-associated SNPs in these genes. The Kita-Nagoya Genomic Epidemiology (KING) study, which was the source of control samples in the present study, was registered in ClinicalTrials.gov (NCT00262691) on 6 December 2005.
  • Takaaki Morimoto, Yohei Mineharu, Koh Ono, Masahiro Nakatochi, Sahoko Ichihara, Risako Kabata, Yasushi Takagi, Yang Cao, Lanying Zhao, Hatasu Kobayashi, Kouji H. Harada, Katsunobu Takenaka, Takeshi Funaki, Mitsuhiro Yokota, Tatsuaki Matsubara, Ken Yamamoto, Hideo Izawa, Takeshi Kimura, Susumu Miyamoto, Akio Koizumi
    PLOS ONE 12(4) e0175649 2017年4月  査読有り
    Background The genetic architecture of coronary artery disease has not been fully elucidated, especially in Asian countries. Moyamoya disease is a progressive cerebrovascular disease that is reported to be complicated by coronary artery disease. Because most Japanese patients with moyamoya disease carry the p.R4810K variant of the ring finger 213 gene (RNF213), this may also be a risk factor for coronary artery disease; however, this possibility has never been tested. Methods and results We genotyped the RNF213 p.R4810K variant in 956 coronary artery disease patients and 716 controls and tested the association between p.R4810K and coronary artery disease. We also validated the association in an independent population of 311 coronary artery disease patients and 494 controls. In the replication study, the p.R4810K genotypes were imputed from genome-wide genotyping data based on the 1000 Genomes Project. We used multivariate logistic regression analyses to adjust for well-known risk factors such as dyslipidemia and smoking habits. In the primary study population, the frequency of the minor variant allele was significantly higher in patients with coronary artery disease than in controls (2.04% vs. 0.98%), with an odds ratio of 2.11 (p = 0.017). Under a dominant model, after adjustment for risk factors, the association remained significant, with an odds ratio of 2.90 (95% confidence interval: 1.37-6.61; p = 0.005). In the replication study, the association was significant after adjustment for age and sex (odds ratio = 4.99; 95% confidence interval: 1.16-21.53; p = 0.031), although it did not reach statistical significance when further adjusted for risk factors (odds ratio = 3.82; 95% confidence interval: 0.87-16.77; p = 0.076). Conclusions The RNF213p.R4810K variant appears to be significantly associated with coronary artery disease in the Japanese population.
  • Fen Huang, Sahoko Ichihara, Yuki Yamada, Shameema Banu, Gaku Ichihara
    Journal of applied toxicology : JAT 37(3) 331-338 2017年3月  査読有り
    The pathophysiology of hypertension is complex and multifactorial, and includes exposure to various chemical substances. Several recent studies have documented the reproductive and neurological toxicities of 1-bromopropane (1-BP). Given that 1-BP increased reactive oxygen species in the brain of rats, we hypothesized that 1-BP also has cardiovascular toxicity through increased oxidative stress. To test this hypothesis, male F344 and Wistar Nagoya rats (n = 7-8 per group per test) were exposed to 0 or 1000 ppm of 1-BP via inhalation for 4 weeks (8 h per day, 7 days per week). The exposure to 1-BP increased systolic blood pressure. This effect was associated with a significant decrease in the reduced/oxidized glutathione ratio. A significant increase in nitrotyrosine levels, activation of the NADPH oxidase pathway, which was evidenced by upregulation of gp91phox, a NADPH oxidase subunit, and significant decreases in the expressions of antioxidant molecules such as Cu/Zn- and Mn-superoxide dismutase catalase, and nuclear factor erythroid 2-related factor 2, were observed in the aortas of Wistar Nagoya rats exposed to 1-BP. Our results indicate that subacute (4-week) inhalation exposure to 1-BP increases blood pressure and suggest that this cardiovascular toxic effect is due, at least in part, to increased oxidative stress mediated through activation of the NADPH oxidase pathway. Further study is needed to assess whether NADPH oxidase activation causes the increase in blood pressure in the rats exposed to 1-BP. Copyright © 2016 John Wiley & Sons, Ltd.
  • Yuki Kitamura, Ryoko Usami, Sahoko Ichihara, Hirotaka Kida, Masayuki Satoh, Hidekazu Tomimoto, Mariko Murata, Shinji Oikawa
    NEUROLOGICAL RESEARCH 39(3) 231-238 2017年  査読有り
    Objectives: Alzheimer's disease (AD) is the most common cause of dementia in elderly persons. Since the pathology of AD develops slowly from a preclinical or early phase into a fully expressed clinical syndrome, at the time of diagnosis the disease has been progressing for many years. To facilitate the early diagnosis of AD, we performed protein profiling of blood in patients with mild AD as defined by the Functional Assessment Staging (FAST) scale. Methods: Plasma samples from mild AD patients and healthy controls were analyzed using two-dimensional differential gel electrophoresis (2D-DIGE) combined with matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF/MS) followed by peptide mass fingerprinting. Results: Three downregulated proteins were identified: apolipoprotein A-1, alpha-2-HS-glycoprotein, and afamin. Two proteins, including apolipoprotein A-4 and fibrinogen gamma chain, were upregulated in mild AD patients. Discussion: Our results suggest that altered expression levels of these proteins in plasma may yield candidate biomarkers for the early diagnosis of AD.
  • Cai Zong, Xiao Zhang, Chinyen Huang, Jie Chang, C Edwin Garner, Toshihiro Sakurai, Masashi Kato, Sahoko Ichihara, Gaku Ichihara
    Toxicology research 5(6) 1522-1529 2016年11月1日  査読有り
    1-Bromopropane (1BP) is widely used as an alternative to ozone-depleting solvents. The present study investigated the role of P450s in 1BP-induced male reproductive toxicity. Mice co-treated with 1-aminobenzotriazole (ABT), a non-selective P450 inhibitor, were exposed to 1BP at 0, 50, 250, or 1200 ppm, while saline-treated control mice were exposed to 1BP at 0, 50, or 250 ppm, for 4 weeks. In the saline-treated mice, exposure to 1BP at 250 ppm decreased the sperm count and sperm motility. Histopathological examination showed that exposure to 1BP at 50 and 250 ppm increased the number of elongated spermatids retained at the basal region of stage IX, X and XI seminiferous tubules, while exposure to 1BP at 250 ppm increased the number of periodic acid-Schiff (PAS)-positive round structures in stage IX, X, and XI seminiferous tubules. Co-treatment with ABT prevented the above changes induced by exposure to 1BP at 50 or 250 ppm. However, ABT-treated mice exposed to 1BP in the 1200 ppm group showed decreases in the weights of reproductive organs, epididymal sperm count and motility, increases in epididymal sperm with abnormal heads, retained spermatids and PAS-positive round structures in stages IX-XI, depletion of spermatogenic cells in part of the seminiferous tubules, and a small number of round spermatids in stage VII seminiferous tubules. The results at 50 and 250 ppm of 1-BP exposure indicate that P450s play important roles in 1BP-induced testicular toxicity. The control of P450 activity reduced 1BP-induced male reproductive toxicities including spermiation failure, reduction of epididymal sperm count and motility, and formation of PAS-positive round structures at postspermiation stages.

MISC

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共同研究・競争的資金等の研究課題

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